Crash when joining Realm - java.lang.NullPointerException: mouseClicked event handler

I looked at the crash report, and I am unable to understand what it meant, so hopefully somebody here can understand what went wrong. I was having issues dropping the file in so I'm copying and pasting the text.

Description: mouseClicked event handler

java.lang.NullPointerException: mouseClicked event handler
	at dhv.a(SourceFile:950)
	at djr.a(SourceFile:284)
	at djr.a(SourceFile:149)
	at djr$$Lambda$2984/573225871.onPress(Unknown Source)
	at dni.b(SourceFile:33)
	at dnc.a(SourceFile:16)
	at dng.a(SourceFile:149)
	at doe.a(SourceFile:27)
	at dly.b(SourceFile:92)
	at dly$$Lambda$2953/1266282188.run(Unknown Source)
	at dqs.a(SourceFile:431)
	at dly.a(SourceFile:92)
	at dly.c(SourceFile:162)
	at dly$$Lambda$2952/1639852645.run(Unknown Source)
	at amn.execute(SourceFile:94)
	at dly.b(SourceFile:162)
	at dly$$Lambda$2303/185596009.invoke(Unknown Source)
	at org.lwjgl.glfw.GLFWMouseButtonCallbackI.callback(GLFWMouseButtonCallbackI.java:36)
	at org.lwjgl.system.JNI.invokeV(Native Method)
	at org.lwjgl.glfw.GLFW.glfwPollEvents(GLFW.java:3101)
	at com.mojang.blaze3d.systems.RenderSystem.flipFrame(SourceFile:102)
	at dgy.e(SourceFile:308)
	at dlx.e(SourceFile:1041)
	at dlx.e(SourceFile:654)
	at net.minecraft.client.main.Main.main(SourceFile:215)